People infected with HIV are more than twice as likely to die from sudden cardiac death (SCD) compared to the general population and are more likely to have their heart compromised by fibrosis, a factor that may play a role in the increase. of its susceptibility to SCD, according to new findings from a study by UC San Francisco.
In addition, the study revealed that one-third of the sudden deaths initially attributed to cardiac causes among the HIV population resulted, in contrast, from drug overdoses in which there was no apparent evidence of drug use at the site.
The results, published on June 17, 2021 in New England Journal of Medicine (NEJM) are the latest developments in the Postmortem InvesTigation of Sudden Cardiac Death (POST SCD) study, which examined unexpected sudden deaths in San Francisco from 2011 to 2016.
POST SCD is an idea of Zian H. Tseng, MD, MAS, cardiac electrophysiologist and professor in the UCSF Department of Medicine. The main interest of Tseng’s research is to discover genetic, molecular or other risk factors sudden cardiac death—One of the leading causes of death from heart disease— which can be used to predict who may benefit most from preventive interventions, such as the implantation of a cardiac defibrillator.
For the current study, Tseng and his team integrated a comprehensive review of medical records and EMS with a complete autopsy, including histology and toxicology, with the goal of discovering the true underlying causes of sudden death in the context of HIV. .
“We found that the sudden death rate is more than double that high among people living with HIV,” said Tseng, lead author of the new study. “If you reduce the focus to sudden death caused by cardiac arrhythmias, the rate in this study was 87 percent higher.”
Questioning the alleged causes of death
Sudden cardiac death occurs when the electrical signaling in the heart is abruptly twisted and the heart stops pumping blood. Risk factors include coronary artery disease, heart attack, and previously diagnosed arrhythmias, but SCD often kills people without previously identified risks.
Tseng first imagined POST SCD when he identified the need to more accurately identify cases of sudden cardiac death, after the results of his retrospective study of a potential risk factor gene in survivors of cardiac arrest documented would not be in agreement with a known previous study. in which sudden cardiac deaths were not well investigated.
Cardiac arrest is usually an assessment made by emergency medical personnel at the scene. SCD has traditionally been defined according to the criteria of the World Health Organization (WHO), in which the heart cause can be assumed if the death occurred within one hour after symptoms or if the deceased had been seen. live asymptomatic for the previous 24 hours.
“Almost all of these deaths outside the hospital are never investigated, so it can often be assumed if a sudden death was due to cardiac causes,” Tseng said. “In my opinion, the researchers have not advanced towards the discovery risk factors for sudden cardiac death, because we previously mixed many non-cardiac conditions in studies in which SCD has been presumed. “
Uniquely, POST SCD relied on autopsies and blood tests as a kind of gold standard for assessing deaths. All sudden deaths outside the hospital should be reported to the medical examiner, but in most jurisdictions autopsies are becoming increasingly rare, except in cases of criminal investigation. Tseng launched the study in collaboration with Ellen Moffatt, MD, a forensic pathologist and forensic assistant for the San Francisco City and San Francisco County Chief Medical Officer’s Office, and an associate clinical professor in the Department of Pathology and Laboratory Medicine at UCSF. . Moffatt autopsied each individual whose death was initially classified as sudden cardiac death.
Half of sudden deaths from other causes
Although heart disease is the leading cause of death in the United States, much of which is due to SCD, the results of Tseng’s studies three years ago showed that about half of sudden deaths attributed to conditions heart attacks were really due to other causes.
“This was a discovery that changed the paradigm and is still making its way into the field of cardiology. We can’t delve into the study and prevention of SCD unless we know which cases are really cardiac.” Tseng said. In addition to drug overdoses, the actual causes of death initially attributed to heart conditions include pulmonary embolism, stroke, infection, diabetic ketoacidosis, gastrointestinal hemorrhage, renal failure, seizures, and rupture of the aneurysm.
In the early days of POST SCD, Tseng noticed that there was a disproportionate number of deaths classified as sudden cardiac deaths in the HIV population. He contacted UCSF fellow Priscilla Hsue, MD, head of the Cardiology Division at Zuckerberg San Francisco General Hospital and Trauma Center and a leading expert on heart disease in people infected with HIV, and together they decided to delve deeper into SCD research in people living with HIV. In their initial analysis, published in 2012, they reported that SCD rates were more than four times higher among people living with HIV, but in this study it was assumed that conventional SCDs did not require autopsy confirmation. .
In the follow-up analysis published now in NEJM, UCSF scientists reported that presumed CDM in HIV-positive and HIV-negative populations occurred at a rate of 53.3 versus 23.7 events per 100,000 person-years, respectively.
There were 610 unexpected deaths among the HIV-positive population, including 109 deaths from a cardiac arrest outside the hospital. Review of medical and paramedical records, forensic examination, and autopsy of all but one of the 109 cases pointed to many underlying causes of death. Of these, 48 met the criteria for presumed CDM, but only 22 of these sudden deaths were caused by arrhythmia, with coronary artery disease, damaged or enlarged heart chambers or pre-existing arrhythmic disease.
Drug overdoses detected by post-mortem toxicology accounted for 16 HIV-positive deaths, 34% of the alleged SCD group. In comparison, among those who were HIV-negative, overdoses accounted for 13 percent of the 505 deaths initially classified as SCD. Other non-arrhythmic causes of death in HIV-positive people with suspected SCD included renal failure, infection, hemorrhage, and diabetic ketoacidosis.
Hsue, who is the lead author of the study, said it is now clear that chronic inflammation in HIV-infected people persists even as part of effectively treating and suppressing HIV disease. In turn, this ongoing inflammation strongly predicts clinical events, including general mortality and cardiovascular events, kidney disease, and neurological disease. People with HIV infection are now known to have significantly higher rates of acute myocardial infarction, heart failure, peripheral arterial disease, and ischemic stroke compared with general population.
The researchers also measured higher levels of interstitial fibrosis, in which collagen is placed around groups of heart cells, in the color tissue of HIV-positive individuals. Similar fibrosis has been observed in lymph nodes, liver and kidneys in previous HIV studies.
“I would hypothesize that this fibrosis would likely represent a systemic impact of chronic HIV infection,” Hsue said. “Our evidence from this study also suggests that there were even higher levels of interstitial fibrosis among the subgroup of HIV-infected individuals with sudden cardiac death and also among those with confirmed autopsy. death by arrhythmias. In the future, it will be crucial to expand this finding by identifying people at risk in order to prevent sudden deaths among people with HIV. In addition, therapeutic strategies to reduce fibrosis will be an important area to advance research. For me, this represents a truly unique study that highlights multidisciplinary collaborations at UCSF. ”
University of California, San Francisco
Citation: Sudden cardiac death is more likely to fall people with HIV infection (2021, June 16) recovered on June 16, 2021 at https://medicalxpress.com/news/2021-06-sudden-cardiac-death- fell-persons.html
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